Benefits of Adhering to the Canadian Physical Activity Guidelines for Adults with Multiple Sclerosis Beyond Aerobic Fitness and Strength

Background

The Canadian Physical Activity Guidelines for Adults with Multiple Sclerosis (PAGs) were released in 2013 but have yet to be validated. We aimed to test the effectiveness of the PAGs in improving fitness, mobility, fatigue symptoms, and quality of life (QOL) in a large cohort of adults with multiple sclerosis (MS).

Methods

As part of an ongoing randomized controlled trial examining implementation of the PAGs, participants were randomized to either a direct referral group (physician referral to an exercise program following the PAGs; n = 42) or a control group (provided a print copy of the PAGs; n = 37). Physical activity behavior was assessed through weekly physical activity logs. Fitness, mobility, fatigue symptoms, and QOL were assessed at baseline and after 16 weeks. Participants were categorized as either PAG adherers (n = 30) or nonadherers (n = 49) to the PAGs based on achieving the weekly exercise recommendations at least 75% of the time.

Results

Adherence to the PAGs was twice as high in the referral group compared with the control group. Adherers experienced significantly greater improvements in peak oxygen consumption (29%), strength (7%-18%), mobility (16%), fatigue symptoms (-36%), and QOL (17%-22%) compared with nonadherers (P < .05).

Conclusions

Following the PAGs for at least 12 of 16 weeks results in improvements in fitness, mobility, fatigue symptoms, and QOL, confirming their effectiveness for improving health in people with MS.

Waist circumference at five common measurement sites in normal weight and overweight adults: which site is most optimal?

The aim of this study was to determine (i) if adults would measure their own waist circumference (WC), (ii) which WC site(s) are the most intuitive and easy to measure and (iii) if measurement accuracy and association between WC and blood pressure differs across five measurement sites. Participants (n = 198) measured their WC first with no instruction and then using visual instructions for the iliac crest, last rib, midpoint, minimal waist and umbilicus. Without instruction, men most commonly measured their WC at the umbilicus and iliac crest, while women measured their WC at the umbilicus and minimal WC. Both men and women reported the minimal waist and umbilicus to be moderately easier to self-measure compared to the other sites (P < 0.05). Prevalence of abdominal obesity varied significantly by gender and measurement site, especially for females (normal weight: 0-18%; overweight: 51-79%). Measurement site did not influence accuracy of WC self-measurement or the association between WC and blood pressure (P > 0.05). A universal WC landmark is needed. From these results, there does not appear to be a clear clinical advantage in terms of blood pressure or practical advantage of measuring one WC site over another. However, the umbilicus may be the most intuitive and easy to measure.

Calorie Estimation in Adults Differing in Body Weight Class and Weight Loss Status

PURPOSE

Ability to accurately estimate calories is important for weight management, yet few studies have investigated whether individuals can accurately estimate calories during exercise or in a meal. The objective of this study was to determine if accuracy of estimation of moderate or vigorous exercise energy expenditure and calories in food is associated with body weight class or weight loss status.

METHODS

Fifty-eight adults who were either normal weight (NW) or overweight (OW), and either attempting (WL) or not attempting weight loss (noWL), exercised on a treadmill at a moderate (60% HRmax) and a vigorous intensity (75% HRmax) for 25 min. Subsequently, participants estimated the number of calories they expended through exercise and created a meal that they believed to be calorically equivalent to the exercise energy expenditure.

RESULTS

The mean difference between estimated and measured calories in exercise and food did not differ within or between groups after moderate exercise. After vigorous exercise, OW-noWL overestimated energy expenditure by 72% and overestimated the calories in their food by 37% (P < 0.05). OW-noWL also significantly overestimated exercise energy expenditure compared with all other groups (P < 0.05) and significantly overestimated calories in food compared with both WL groups (P < 0.05). However, among all groups, there was a considerable range of overestimation and underestimation (-280 to +702 kcal), as reflected by the large and statistically significant absolute error in calorie estimation of exercise and food.

CONCLUSIONS

There was a wide range of underestimation and overestimation of calories during exercise and in a meal. Error in calorie estimation may be greater in overweight adults who are not attempting weight loss.

Lifestyle and weight predictors of a healthy overweight profile over a 20-year follow-up

OBJECTIVE

To examine whether changes in modifiable risk factors [physical activity, cardiorespiratory fitness (CRF), body weight, and diet composition] are associated with the transition to metabolically healthy overweight/obese (MHOW) versus metabolically abnormal overweight/obese.

METHODS

Analysis included 1,358 adults [aged 25.0 (3.5) years] from the CARDIA study who were healthy at baseline and had overweight/obesity at follow-up. Participants with zero or one of the following six risk factors were classified as MHOW: elevated triglycerides, LDL, blood pressure, fasting glucose, and HOMA-insulin resistance and low HDL.

RESULTS

Over the 20-year follow-up, the sample gained weight (BMI 24.5 to 31.1 kg/m(2) ), and the prevalence of MHOW was 47% at follow-up. After adjusting for changes in CRF, diet, and weight change, physical activity and macronutrient intake were not independently associated with MHOW (P > 0.05), while changes in CRF [fit-unfit: RR (95%) = 0.58, 0.52-0.66; unfit-unfit: RR = 0.67, 0.58-0.76, versus fit-fit] and weight [gain: RR (95%) = 0.54, 0.43-0.67; cycle: RR = 0.74, 0.57-0.94, versus stable] were independently associated with MHOW.

CONCLUSIONS

Focusing on high CRF and strategies to limit weight gain may be important for individuals with overweight and obesity in early to mid-adulthood to maintain a metabolically healthy profile.

Edmonton Obesity Staging System Prevalence and Association with Weight Loss in a Publicly Funded Referral-Based Obesity Clinic

OBJECTIVES

To determine the distribution of EOSS stages and differences in weight loss achieved according to EOSS stage, in patients attending a referral-based publically funded multisite weight management clinic.

SUBJECTS/METHODS

5,787 obese patients were categorized using EOSS staging using metabolic risk factors, medication use, and severity of doctor diagnosis of obesity-related physiological, functional, and psychological comorbidities from electronic patient files.

RESULTS

The prevalence of EOSS stages 0 (no risk factors or comorbidities), 1 (mild conditions), 2 (moderate conditions), and 3 (severe conditions) was 1.7%, 10.4%, 84.0%, and 3.9%, respectively. Prehypertension (63%), hypertension (76%), and knee replacement (33%) were the most common obesity-related comorbidities for stages 1, 2, and 3, respectively. In the models including age, sex, initial BMI, EOSS stage, and treatment time, lower EOSS stage and longer treatment times were independently associated with greater absolute (kg) and percentage of weight loss relative to initial body weight (P < 0.05).

CONCLUSIONS

Patients attending this publicly funded, referral-based weight management clinic were more likely to be classified in the higher stages of EOSS. Patients in higher EOSS stages required longer treatment times to achieve similar weight outcomes as those in lower EOSS stages.

Individuals underestimate moderate and vigorous intensity physical activity

BACKGROUND

It is unclear whether the common physical activity (PA) intensity descriptors used in PA guidelines worldwide align with the associated percent heart rate maximum method used for prescribing relative PA intensities consistently between sexes, ethnicities, age categories and across body mass index (BMI) classifications.

OBJECTIVES

The objectives of this study were to determine whether individuals properly select light, moderate and vigorous intensity PA using the intensity descriptions in PA guidelines and determine if there are differences in estimation across sex, ethnicity, age and BMI classifications.

METHODS

129 adults were instructed to walk/jog at a "light," "moderate" and "vigorous effort" in a randomized order. The PA intensities were categorized as being below, at or above the following %HRmax ranges of: 50-63% for light, 64-76% for moderate and 77-93% for vigorous effort.

RESULTS

On average, people correctly estimated light effort as 51.5±8.3%HRmax but underestimated moderate effort as 58.7±10.7%HRmax and vigorous effort as 69.9±11.9%HRmax. Participants walked at a light intensity (57.4±10.5%HRmax) when asked to walk at a pace that provided health benefits, wherein 52% of participants walked at a light effort pace, 19% walked at a moderate effort and 5% walked at a vigorous effort pace. These results did not differ by sex, ethnicity or BMI class. However, younger adults underestimated moderate and vigorous intensity more so than middle-aged adults (P<0.05).

CONCLUSION

When the common PA guideline descriptors were aligned with the associated %HRmax ranges, the majority of participants underestimated the intensity of PA that is needed to obtain health benefits. Thus, new subjective descriptions for moderate and vigorous intensity may be warranted to aid individuals in correctly interpreting PA intensities.

All-cause and cardiovascular mortality risk in U.S. adults with and without type 2 diabetes: Influence of physical activity, pharmacological treatment and glycemic control

AIMS

This study determined the joint association between physical activity, pharmacotherapy, and HbA1c control on all-cause and cardiovascular disease (CVD) mortality risk in adults with and without type 2 diabetes (T2D).

METHODS

12,060 adults from NHANES III and NHANES continuous (1999-2002) surveys were used. Cox proportional hazards analyses were included to estimate mortality risk according to physical activity, pharmacotherapy, and glycemic control (HbA1c <7.0%) status, with physically active, treated and controlled (goal situation) as the referent.

RESULTS

Compared to the referent, adults with T2D who were uncontrolled, or controlled but physically inactive had a higher all-cause mortality risk (p<0.05). Compared to the referent, only adults with T2D who were physically inactive had a higher CVD mortality risk, regardless of treatment or control status (p<0.05). Normoglycemic adults had a similar all-cause and CVD mortality risk as the referent (p>0.05).

CONCLUSIONS

Physical activity and glycemic control are both associated with lower all-cause and CVD mortality risk in adults with T2D. Adults with T2D who are physically active, pharmacologically treated, and obtain glycemic control may attain similar mortality risk as normoglycemic adults.

The joint association of physical activity, blood-pressure control, and pharmacologic treatment of hypertension for all-cause mortality risk

BACKGROUND

We conducted a study to determine the joint association of physical activity, pharmacologic treatment for hypertension, and the control of blood pressure (BP) on all-cause mortality risk.

METHODS

The study subjects were 10,665 adults from the Third National Health and Nutrition Examination Survey (NHANES III) and the Continuous NHANES survey (1999-2000 and 2000-2001). Cox proportional hazards analyses were used to estimate differences in mortality risk according to physical activity, pharmacologic treatment for hypertension, and BP control, with physically active, treated, and controlled as the referent category.

RESULTS

The average follow-up time in the study was 8.6±4.8 years. The main effect of physical activity was significant independently of pharmacologic treatment and BP control (P < 0.001). Physically inactive adults with hypertension had a higher risk of mortality than did physically active adults with treated and controlled hypertension (inactive, treated and controlled hypertension: HR, 1.42; 95% CI, 1.17-1.72; P < 0.01; inactive, treated, and uncontrolled hypertension: HR, 1.55; 95% CI, 1.30-1.84; P < 0.01; inactive, untreated, and uncontrolled hypertension: HR, 1.27; 95% CI, 1.07-1.52, P < 0.01). However, the risk of mortality for physically active adults with hypertension did not differ significantly with or without treatment for hypertension if their hypertension remained uncontrolled (active, treated and uncontrolled hypertension: HR, 1.17; 95% CI 0.98-1.40; P = 0.08; active, untreated and uncontrolled hypertension: HR, 0.90; 95% CI, 0.76-1.08; P = 0.25). Physically active, normotensive individuals had a lower all-cause mortality risk than did the referent group of physically active individuals being treated with antihypertensive medication and who had controlled hypertension (HR, 0.72; 95% CI, 0.60-0.86; P < 0.01), whereas physically inactive, normotensive individuals had a risk of mortality similar to that of the referent group (HR, 1.08; 95% CI, 0.90-1.30; P = 0.42).

CONCLUSION

Physical activity may be as or even more important than pharmacotherapy for reducing the risk of mortality in adults with hypertension. However, the risk of mortality remained higher for physically active adults with treated and controlled hypertension than did the risk of mortality for physically active normotensive populations. Prevention of hypertension is therefore imperative for reducing the all-cause risk of premature mortality in adults.

The Association Between Frequency of Physical Activity and Mortality Risk Across the Adult Age Span

Objectives: To determine if the association between frequency of leisure-time physical activity and mortality risk differs across adulthood. Method: 9,249 adults from the NHANES III (1988-1994) were categorized as middle-aged (40-64 years), old (65-79 years) or very old (≥80 years), and as inactive (0 bouts of physical activity/week), lightly active (1-2 bouts/week), moderately active (3-4 bouts/week) or very active (5+ bouts/week). Results: In all age categories, lightly, moderately, and very active adults had a lower mortality risk compared to inactive adults ( p < .001). In very old adults only, being very active was associated with a lower mortality risk compared to being lightly active (HR 0.80, 95% CI 0.64-0.98; p = .03) and moderately active (HR 0.80, 95% CI 0.65-0.98; ( p = .03). Discussion: The association between physical activity frequency and mortality risk is strongest in very old adults. All adults and particularly very old adults may benefit from participating in physical activity five or more times a week.

Relationship between obesity and obesity-related morbidities weakens with aging

BACKGROUND

A weak relationship exists between obesity and mortality risk in older populations, however, the influence of age on the relationship between obesity and morbidity is unclear. The objective of this study was to determine the influence of age on the relationship between obesity and cardiovascular disease, type 2 diabetes, dyslipidemia, and hypertension.

METHODS

Data from the Third National Health and Nutrition Examination Survey (1988-1994) were used. Individuals were classified into specific age (young: 18-40; middle: 40-65; old: 65-75; and very old: ≥75 years) and body mass index (BMI; 18.5-24.9, >25-29.9, ≥ 30kg/m(2)) categories. Cardiovascular disease, type 2 diabetes, dyslipidemia, and hypertension were categorized using measured metabolic risk factors, physician diagnosis, or medication use.

RESULTS

Age modified the relationship between BMI and cardiovascular disease (Age × BMI interaction, p = .049), dyslipidemia (Age × BMI interaction, p = .035 for men, p < .001 for women), and hypertension (Age × BMI interaction, p = .023) in women but not in men (p = .167). However, age did not modify the relationship between BMI and type 2 diabetes (Age × BMI interaction, p = .177). BMI was strongly associated with increased relative risk of cardiovascular disease, dyslipidemia, type 2 diabetes, and hypertension in the young and middle aged, however, the association between BMI and these metabolic conditions were much more attenuated with increasing age.

CONCLUSION

A stronger association between obesity and prevalent metabolic conditions exists in young and middle-aged populations than in old and very old populations. Longitudinal studies are needed to verify these findings and to confirm the benefits of weight loss on health across the life span.